Food Web

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Across
  1. 2. substances released into the air.
  2. 4. fuels fuel formed from ancient organisms.
  3. 5. fixation converting nitrogen gas into usable forms.
  4. 9. the layer of gases around earth.
  5. 10. necessary.
  6. 13. converting nitrogen into nitrates in soil.
  7. 14. burning.
  8. 15. work or act together.
  9. 17. a gas essential for life.
  10. 18. development of cities.
Down
  1. 1. plants making food using sunlight.
  2. 3. growing crops and raising animals.
  3. 6. control or manage.
  4. 7. water falling from clouds.
  5. 8. breaking down dead matter.
  6. 11. related to industry and manufacturing.
  7. 12. using resources without depleting them.
  8. 16. releasing energy from food.